mm: khugepaged: set to next mm direct when mm has MMF_DISABLE_THP_COMPLETELY

When an mm with the MMF_DISABLE_THP_COMPLETELY flag is detected during
scanning, directly set khugepaged_scan.mm_slot to the next mm_slot, reduce
redundant operation.

Without this patch, entering khugepaged_scan_mm_slot() next time, we will
set khugepaged_scan.mm_slot to the next mm_slot.

With this patch, we will directly set khugepaged_scan.mm_slot to the next
mm_slot.

Link: https://lkml.kernel.org/r/20260207081613.588598-6-vernon2gm@gmail.com
Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 1dd3cfca610db91133eeb569f46f837acce517c5..17ab58681032b33877ce62d3198fe400473c0f4c 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2508,9 +2508,9 @@ breakouterloop_mmap_lock:
        VM_BUG_ON(khugepaged_scan.mm_slot != slot);
        /*
         * Release the current mm_slot if this mm is about to die, or
-        * if we scanned all vmas of this mm.
+        * if we scanned all vmas of this mm, or THP got disabled.
         */
-       if (hpage_collapse_test_exit(mm) || !vma) {
+       if (hpage_collapse_test_exit_or_disable(mm) || !vma) {
                /*
                 * Make sure that if mm_users is reaching zero while
                 * khugepaged runs here, khugepaged_exit will find